Kue - Longtooth grouper

A marine fish belonging to the order Perciformes, family Serranidae, subfamily Corbicula, tribe Epinephelinae. It is found in the waters of the Sea of ​​Japan coast from Aomori and Niigata prefectures to the northwestern coast of Kyushu, Chiba prefecture, the Pacific coast from Sagami Bay to Yakushima, Okinawa Island, the Korean peninsula, Taiwan, the South China Sea, and the waters of Hainan Island. It belongs to the genus Epinephelinus, which has 11 dorsal fin spines and usually 8 anal fin rays. The body is slightly long and laterally compressed, and the outer contour of the back of the head rises gently and almost uniformly. There are clear, somewhat large serrations on the corner of the preopercle. The dorsal edge of the opercle is convex, and the upper spine is not prominent. The mouth is large, and the rear end of the upper jaw extends beyond the rear edge of the eye. The lower jaw has two rows of well-developed canines in the middle of the sides, larger than those in the upper jaw. The dorsal fin has 11 spines and 13-15 soft rays, the anal fin has 3 spines and 8 soft rays (rarely 9 rays). The rear edge of the caudal fin is rounded. The scales are small, at least on the sides of the body, and are pectinate. Small scales are embedded above the main maxilla. There are 64-72 pore-like scales on the lateral line. In adults, the scales in front of the lateral edge become branched tubular. The body is gray-brown with six oblique bands on the sides, each with irregular pale markings. The first band is just before the dorsal fin origin, and the last band is on the caudal peduncle. In adults over 40 cm long, the bands are only present on the back or are absent, and the sides are covered with small pale gray spots. Juvenile fish live in coastal eelgrass beds, and as they grow, they move from coastal reefs to deeper waters. They do not form schools, but live alone in rock holes in the reefs. They stay in their holes during the day, but are active at night, searching for food such as shrimp, crabs, and fish. They are not afraid of predators, and will come close to divers.

This species is about 1 meter long and undergoes protogynous sex change from female to male, but the details are unknown. The spawning season is around June, and in captivity, males have been observed repeatedly shaking their tails in front of females, then rising to the water surface in pairs to spawn and release sperm. The eggs are 0.84-0.96 mm in diameter and are pelagic, and the hatched larvae are 2 mm long. In September and October, juvenile fish with a total length of about 20 mm are collected from tide pools. The larvae and juveniles have long second dorsal and pelvic fin spines, and a long spine at the corner of the preopercle, but these spines become less noticeable as they grow. They grow to a body length of about 23 cm in one year, and can reach a maximum total length of 40 cm. They are caught using bottom gill nets, bottom longlines, bottom trawls, and fishing. Older adult fish are called moroko and are a popular target fish for big game fishing. The flesh is white and is washed, served as sashimi, or in a hotpot. It is the tastiest of all groupers and has high commercial value. There are efforts being made to develop seed production techniques for culturing this fish. It is difficult to distinguish from older adult fish of the closely related red spotted grouper, but the red spotted grouper has serrated edges on the lower edge of its preopercle, which allows it to be distinguished from the grouper.

[Masao Katayama and Kunio Amanooka, December 11, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

硬骨魚綱スズキ目ハタ科ハタ亜科ハタ族に属する海水魚。青森県、新潟県から九州北西岸の日本海沿岸、千葉県、相模(さがみ)湾から屋久島(やくしま)の太平洋沿岸、沖縄本島、朝鮮半島、台湾、南シナ海、海南島の海域などに分布する。背びれ棘(きょく)が11本、臀(しり)びれ軟条が通常8本のマハタ属に含まれる。体はやや長く側扁(そくへん)し、頭部背面の外郭は緩くほぼ一様に上昇する。前鰓蓋骨(ぜんさいがいこつ)の隅角(ぐうかく)部に明瞭(めいりょう)に、いくぶん大きな鋸歯(きょし)がある。主鰓蓋骨の背縁は凸状で、上の棘は不顕著。口は大きく、上顎(じょうがく)の後端は目の後縁を越える。下顎の側中央部に2列のよく発達した犬歯があり、上顎のものより大きい。背びれは11棘13～15軟条、臀びれは3棘8軟条（まれに9軟条）。尾びれの後縁は丸い。鱗(うろこ)は小さく、少なくとも体側面では櫛鱗(しつりん)。主上顎骨の上に小鱗が埋まる。側線有孔鱗数は64～72枚。成魚では側縁の前の数鱗は分枝した管状になる。体は灰褐色で、側面に6本の斜めの帯状斑(はん)があり、各斑のなかに不規則な淡色の斑紋がある。第1帯は背びれ起部直前に、最後の斑は尾柄(びへい)上にある。40センチメートルを超える成魚では、帯状斑は背部にのみみられるか、もしくは消失しており、側面は小さい淡灰色の斑点で覆われる。幼魚は沿岸のアマモ場で生息し、成長するにつれて沿岸の岩礁域から深みへ移動する。群れをなさず、岩礁域の岩穴に単独ですむ。昼間は穴の中にいるが、夜間はエビ・カニ類、魚類など餌(えさ)を求めて活動する。外敵を恐れない魚で、ダイバーの近くにも寄ってくる。

　本種は体長約1メートルで雌から雄に雌性先熟型の性転換を行うが、詳細は不明である。産卵期は6月ごろで、飼育による観察では、雄が雌の前で尾部を震わせる行動を繰り返した後に、対(つい)で何回も水面に向かって上昇し、産卵と放精をするようすがみられた。卵径は0.84～0.96ミリメートルの分離浮性卵で、孵化仔魚(ふかしぎょ)は体長2ミリメートル。9～10月に全長20ミリメートルぐらいの幼魚が潮だまり（タイドプール）で採集される。仔稚魚は第2背びれ棘と腹びれ棘が長く、また前鰓蓋骨の隅角部に長い1本の棘があるが、これらの棘は成長するにつれて目だたなくなる。1年で体長23センチメートルほどになり、最大全長は40センチメートルに達する。底刺網(そこさしあみ)、底延縄(そこはえなわ)、底引網、釣りなどで漁獲される。老成魚はモロコとよばれて、大物釣りの対象魚として人気がある。肉は白身で、洗い、刺身、ちり鍋(なべ)などにする。ハタ類中もっとも美味で、商品価値は高い。養殖魚として種苗生産技術の開発が試みられている。近縁種のマハタの老成魚と判別がむずかしいが、マハタには前鰓蓋骨の下縁に鋸歯(きょし)があることでクエと区別できる。

［片山正夫・尼岡邦夫　2020年12月11日］

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